The objective of this research is to study the regulation of coordinated gene activity in a eukaryote. To this end, the phenomenon of dosage compensation in Drosophila is being investigated since it represents a regulatory mechanism which deals with differences in the number (or doses) of X-linked genes normally occurring between males and females. The long-term goal of the proposed research is to understand a level of genetic organization which is not found among simpler prokaryotic organisms since it was evolved in higher multicellular forms to accomodate specific necessities of their reproductive biology and development. BIBLIOGRAPHIC REFERENCES: Bewley, G.C. and J.C. Lucchesi. 1976. Developmental effects of alpha-GPO activity in Drosophila melanogaster. Isozyme Bull. 9 (in press). Lucchesi, J.C. 1976. Interchromosomal effects. In Genetics and Biology of Drosophila, Volume Ia, Chapter 7. M. Ashburner and E. Novitski, Eds. Acad. Press, London.